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Indeed. The movement code just wasn't done for such things.

I seem to get off-and-on results as far as splashes in TH water. Shallower angles appear to cause splashes more easily, so I suppose this has to do with DooM's "dodgy" collision handling.

Yes, it's all very intentional. Transfer_Heights just was never intended for what you are doing. Of course parts could be changed but I don't think it's a good idea to do this 12 years after this feature was born.

Is there a better/recommended way to have something move up from a hidden pit in a liquid surface?



What about floors with no floorclip value? eg, consider the attached modification of the original file (Doom2 this time).
It sets up FLOOR0_3 to make the misc/chat sound when an actor hits it. It has no floorclip value yet the raised floor still doesn't have a sound (ie, jumping up and down on it doesn't bleep like the rest of the room does)



Also, the bottom of the pillars are still clipped off like they would be in OpenGL (seer the one on the right in this pic).




Are both of these things (lack of sound and sprite clipping) also intended/expected behaviour even without a floorclip floor?

And finally, even if you remove the TERRAIN lump from the WAD, obviously you can no longer tell what is happening with the splash, but the pillar sprites still get clipped. Again, this could well be intentional, I'm just checking.

This is all quite intentional. There's even a remark in the source somewhere regarding to this behavior.

Better don't create situations which depend on both default floorclipping and Transfer_Heights. It's just one of these things that just don't work well together.

This has existed for a long time and it's one of those things that I keep forgetting to mention, and now I've finally remembered.

Transfer heights can disable splashes and floorclipping and, as such, can detract from certain effects. Try the example (for Heretic because of its built in splashes). It is a single room with a square pit in the middle hidden by transfer heights. The main outer area generates splashes (easily testable by jumping up and down at the P1 spot. If you switch on chasecam, you can also see that the player is clipped into the floor.

When you walk forward from the P1 spot, the pit rises to match the height of the surrounding sector (the corners of the pit are marked with pillars). Go into the middle area and jump up and down - no splashes. Check chasecam and no floorclip either. Worse, as you move onto and off of the now-risen floor, your view jumps up and down slightly because of the lack of floorclipping.

If you play on hard, there is a golem in the pit. After the pit has raised, you can watch him stepping on and off the pit floor and thereby changing between floor clipping and not floor clipping.

Even if you noclip from the P1 start (thus avoiding triggering the rising pit) and fall into the pit, its floor still does not splash or floorclip in its lowered state.

Interestingly, however, shoot the floor with the magic wand and all areas of the floor at the "normal" height splash - before and after the floor rises - though if you noclip into the pit, the lower floor does not splash.

Another smaller issue that I noticed, you'll see that I have placed a pillar on each corner of the pit both inside and outside the pit. The pillar actor is not set to floorclip so they are all the same height. However, the pillars on the non-transfer height part of the room extend slightly into the ground (as all Doom sprites do when they have offsets that place their bottom edge below the floor). However, the ones on the transfer heights area are clipped at floor level (just like they might be in an OpenGL port).

I'm perfectly prepared to believe that all this behaviour may be intentional to avoid problems elsewhere but, in case it is a bug, there you have it.